As a screen for displaying an image projected from a projector, a reflection type wherein the image from the projector is projected from the viewer side (front side), or a transmission type wherein the image from the projector is projected from the side (back side) opposite to the viewer side, is known.
In a conventional screen in general, when the image was not projected, the viewer was unable to view the other side of the screen. For example, in a transmission type screen, usually irregularities are provided on the surface in order to display an image by scattering light projected from the back side, and although the light from the back side is transmitted, a haze was high and it was difficult for the observer to clearly visually recognize the state of the back side.
In recent years, see-through screens have been proposed whereby it is possible to view the other side of the screens when the image is not projected. For example, the following (1) to (3) have been proposed as screens having see-through properties improved while securing the visibility of the image.
(1) A see-through transmission type screen having a light diffusing layer on at least one side of a light transmissive support such as a polyethylene terephthalate (PET) film, wherein the light diffusion layer comprises light diffusing fine particles made of organic fine particles or inorganic fine particles and a xerogel (a gel having an internal solvent lost by evaporation to have a net-work structure with void spaces) (Patent Document 1).
(2) A semi-transmission type reflective screen which is a screen to reflect image light projected from an image source to let it be visible and which comprises unit prism shapes arranged in plurality in one-dimensional or two-dimensional directions along the screen surface, light-absorbing portions formed between said unit prism shapes and containing microbeads to absorb light, and a reflective transmission layer made of an aluminum-deposited PET film formed on at least the back surface side of the unit prism shapes, to reflect the image light that has passed through the unit prism shapes and to let light from the side opposite to the projection side where the image light is projected, be transmitted (Patent Document 2).
(3) A translucent projector screen containing a polarizing laminate comprising a diffusion-type polarizing layer and an absorption-type polarizing layer, wherein transmission axes of both layers are parallel, and wherein the diffusion-type polarizing layer comprises a continuous phase formed of a first transparent thermoplastic resin such as polycarbonate, and a dispersed phase formed of a second transparent thermoplastic resin such as a polyalkylene naphthalate resin and having a refractive index different from the continuous phase (Patent Document 3).